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USAGE_PROPERTIES structure (winuser.h)

  • Article

Contains device properties (Human Interface Device (HID) global items that correspond to HID usages) for any type of HID input device.

Syntax

typedef struct tagUSAGE_PROPERTIES {
  USHORT level;
  USHORT page;
  USHORT usage;
  INT32  logicalMinimum;
  INT32  logicalMaximum;
  USHORT unit;
  USHORT exponent;
  BYTE   count;
  INT32  physicalMinimum;
  INT32  physicalMaximum;
} USAGE_PROPERTIES, *PUSAGE_PROPERTIES;

Members

level

A usage-specific value for a range-based linear control (knob or dial), an on/off control (toggle switch), a momentary control (mouse button), a one-shot control (button that triggers a single event), or re-trigger control (button that triggers a repeating event).

page

The Usage Page ID, such as VR Controls Page (0x03) or Game Controls Page (0x05).

usage

The Usage ID associated with a Usage Page, such as Turn Right/Left (21) or Move Right/Left (24) for a Game Controls Page.

logicalMinimum

The smallest value that the control can report.

logicalMaximum

The largest value that the control can report.

unit

The standard of measure used to describe a control's physical value (after converting the logical value using the exponent value). The HID specification defines codes for the basic units of length, mass, time, temperature, current, and luminous intensity.

exponent

The value used to scale a logical value to a physical value.

count

The number of data items contained in the report.

physicalMinimum

The logicalMinimum expressed in physical units (converted by multiplying logicalMinimum by exponent).

physicalMaximum

The logicalMaximum expressed in physical units (converted by multiplying logicalMaximum by exponent).

Remarks

The HID working group publishes a set of documents that make up the HID Usage Tables (the dictionary that describes what HID devices are allowed to do). These HID Usage Tables contain a list with Usage descriptions. A Usage provides information to an application developer about the intended meaning and use of a particular item described in the Report Descriptor. For example, there is a Usage defined for the left button of a mouse. The Report Descriptor can define where in a report an application can find the current state of the mouse’s left button. The Usage Tables are broken up into several name spaces, called Usage Pages. Each Usage Page describes a set of related Usages to help organize the document. The combination of a Usage Page and Usage defines the Usage ID that uniquely identifies a specific Usage in the Usage Tables.

Requirements

Requirement Value
Minimum supported client Windows 10, version 1809 [desktop apps only]
Minimum supported server Windows Server [desktop apps only]
Header winuser.h

See also

Universal Serial Bus HID Usage Tables - USB.org